Liu Tingting, Wang Shu, Zhu Ming
School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Proc Math Phys Eng Sci. 2017 Dec;473(2208):20170496. doi: 10.1098/rspa.2017.0496. Epub 2017 Dec 20.
The existing molecular relaxation models based on both parallel relaxation theory and series relaxation theory cannot extract the contributions of gas compositions to acoustic relaxation absorption in mixtures. In this paper, we propose an analytical model to predict acoustic relaxation absorption and clarify composition relaxation contributions based on the rate-determining energy transfer processes in molecular relaxation in excitable gases. By combining parallel and series relaxation theory, the proposed model suggests that the vibration-translation process of the lowest vibrational mode in each composition provides the primary deexcitation path of the relaxation energy, and the rate-determining vibration-vibration processes between the lowest mode and others dominate the coupling energy transfer between different modes. Thus, each gas composition contributes directly one single relaxation process to the molecular relaxation in mixture, which can be illustrated by the decomposed acoustic relaxation absorption spectrum of the single relaxation process. The proposed model is validated by simulation results in good agreement with experimental data such as N, O, CO, CH and their mixtures.
现有的基于平行弛豫理论和串联弛豫理论的分子弛豫模型无法提取气体成分对混合物中声弛豫吸收的贡献。在本文中，我们提出了一个分析模型，用于预测声弛豫吸收，并基于可激发气体中分子弛豫的速率决定能量转移过程来阐明成分弛豫贡献。通过结合平行和串联弛豫理论，所提出的模型表明，每种成分中最低振动模式的振动-平动过程提供了弛豫能量的主要去激发路径，并且最低模式与其他模式之间的速率决定振动-振动过程主导了不同模式之间的耦合能量转移。因此，每种气体成分对混合物中的分子弛豫直接贡献一个单一的弛豫过程，这可以通过单一弛豫过程的分解声弛豫吸收光谱来说明。所提出的模型通过与N、O、CO、CH及其混合物等实验数据吻合良好的模拟结果得到了验证。
